The present invention relates to a chair, preferably of the type adapted for use by handicapped persons, comprising a seat provided with upholstery, and a back rest, a chair frame supporting the seat and the back rest and having, or not, wheels and arm rests fixed in position to the lateral or bottom portions of the seat.
The chairs of the type mentioned above today available on the market suffer from problems as far as the seating comfort is concerned, especially when used by persons who remain seating in the chair for long periods of time. As far as the chair seat is concerned this part has so far not provided the pelvis of the user a satisfactory stability in the rear direction to the back rest. Further, the pressure against the tuberis ischiadicum in combination with the considerable shearing force relatively the seat amount to such a magnitude that the user experiences lack of comfort and so that the soft regions between the seat and the pelvis will get benumbed after some time in the chair. Other problems are that the lower portion of the back rest does not provide adequate space for the pelvis in the rear direction and that the back rest will exert a pressure against the pelvis so that the user tends to slip forwards on the seat and, in the worst case, may fall out of the chair.
When efforts have been made to rectify those problems by tilting the seat backwards, some of the problems are eliminated to a certain extent but, instead other problems will turn up, i.a. that the user assumes a posture too stabilizing backwards to allow him to be active forwards. Also, the tendency for the spine to get compressed does also increase significantly and, already after a few minutes, there arise great problems in the shape of tension in the muscles of the back of the neck. Further, the pressure exerted by the arms against the arm rests can get rather high if the person remains seating in this position for a longer period of time.